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Title: LATE BLIGHT TRIALS IN THE UW BIOTRON IDENTIFY RESISTANT AND SUSCEPTIBLE CLONES IN POTATO BREEDING POPULATIONS

Author
item Haberlach, Geraldine
item NAESS, S - UNIVERSITY OF WISCONSIN
item WIELGUS, S - UNIVERSITY OF WISCONSIN
item RAASCH, J - UNIVERSITY OF WISCONSIN
item Helgeson, John

Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/27/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: S. bulbocastanum, a wild potato relative, may be a source of durable resistance to late blight. We are currently using somatic hybrids of S. bulbcastanum backcrossed to potato in order to identify markers that co-segregate with resistance. An essential component of this study is a reliable assay for late blight resistance. Controlled late blight trials scan be run ten months of the year in greenhouse facilities at the UW biotron. Typical experiments involve 60 - 100 clones in five replicates, randomized on 10-13 mobile carts. Leaf and stem surface areas of 20-30cm tall plants in 4-inch pots are spray inoculated with a fine mist of Phytophthora infestans sporangial suspension (US-8, type A2, Cornell standard ME 93-2A; ~30,000 sporangia/ml; pre- chilled 4 hours at 10 deg C). Humidity is maintained at or above 90% with 23 deg C days and 15 deg C nights. Foliage blight scores are recorded dat 4-5 days, 7 days, 10-11 days and finally 14-15 days. Malcomson's blight scale catagories of 1-9 (1 indicating >90% and 9 indicating 0% necrotic tissue) is used to rate each plant. We added a rating of 0 to indicate total plant destruction. Results from several BC1 and BC2 populations indicate clear segregation for disease resistance and correlate reasonably well with field results in WI and Mexico.